Pole piece, battery cell and battery

Abstract

The utility model relates to the technical field of batteries, in particular to a pole piece, a battery cell and a battery. The pole piece provided by the utility model comprises a pole piece body and a first adhesive layer, the pole piece body comprises a pole piece main body part and pole piece edge parts, the two sides of the pole piece main body part in the width direction are connected with the pole piece edge parts, and the first adhesive layer is coated on the pole piece edge parts. According to the pole piece provided by the utility model, the first adhesive layer is coated on the edge part of the pole piece, so that the adhesive force between the edge part of the pole piece and the diaphragm can be effectively improved, the problem that the edge of a battery cell is warped is avoided, the problem that the thickness of the edge of a battery expands after circulation is reduced, the service life of the battery is prolonged, and the safety of the battery is improved. According to the battery cell and the battery provided by the utility model, by applying the pole piece, the problem of edge warping of the battery cell is avoided, the problem of thickness expansion of the edge of the battery after circulation is reduced, the service life of the battery is prolonged, and the safety of the battery is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially relates to a pole piece, electric core and battery. BACKGROUND

[0002] In lithium ion battery, both sides in the thickness direction of diaphragm are usually coated with polymer coating, thereby improving the adhesion of diaphragm and positive pole piece and negative pole piece, so as to improve the cycle life of battery. But the restraint force of the edge of soft package electric core is weaker than the main part of electric core, and there is more free electrolyte at the top and bottom of battery cavity, so the edge of electric core is prone to edge warping. With the battery cycle, especially high temperature cycle, the edge warping of electric core will intensify, so that the battery edge appears swelling and bulging, thereby affecting the service life and safety of battery.

[0003] Therefore, an electrode tab, an electric core and a battery are needed to solve the above problems. UTILITY MODEL CONTENT

[0004] The utility model aims at providing an electrode tab, an electric core and a battery to improve the adhesion of the edge of the electrode tab and the diaphragm, avoid the edge warping of the electric core, reduce the thickness swelling of the battery edge after cycling, and improve the service life and safety of the battery.

[0005] To achieve this purpose, the utility model adopts the following technical solutions:

[0006] An electrode tab comprises:

[0007] An electrode tab body comprises an electrode tab main part and an electrode tab edge part, and both sides of the electrode tab main part in the width direction are connected with the electrode tab edge part; and

[0008] A first adhesive layer is coated on the electrode tab edge part.

[0009] As an optional solution, the first adhesive layer is a PVDF coating, a PVDF copolymer coating, a PMMA coating, a PMMA copolymer coating, a PMIA coating, a PMIA copolymer coating, a PEI coating, a PEI copolymer coating, a PI coating, a PI copolymer coating, a PAA coating, a PAA copolymer coating, a PU coating, a PU copolymer coating, a PEO coating or a PEO copolymer coating.

[0010] As an optional solution, the thickness h1 of the first adhesive layer coated on the electrode tab edge part is 0.5um-5um.

[0011] As an optional solution, the ratio of the width size w1 of the electrode tab edge part to the width size w2 of the electrode tab main part is 4%-40%.

[0012] As an option, the width dimension w1 of the tab edge portion is 0.4mm to 24mm.

[0013] As an option, the ratio of the thickness h1 of the first adhesive layer to the thickness h2 of the tab body is 0.3% to 5%.

[0014] An electric core comprises a separator and two tabs as described above, the two tabs are positive tab and negative tab respectively, the separator is coated with a second adhesive layer on opposite sides along the thickness direction of the separator, and the positive tab is pasted on one side of the separator along the thickness direction of the separator, and the negative tab is pasted on the other side of the separator along the thickness direction of the separator.

[0015] As an option, the thickness h3 of the second adhesive layer coated on one side of the separator along the thickness direction of the separator is 0.5um to 5um; and / or

[0016] The thickness h4 of the second adhesive layer coated on the other side of the separator along the thickness direction of the separator is 0.5um to 5um.

[0017] As an option, the second adhesive layer is PVDF coating, PVDF copolymer coating, PMMA coating, PMMA copolymer coating, PMIA coating, PMIA copolymer coating, PEI coating, PEI copolymer coating, PI coating, PI copolymer coating, PAA coating, PAA copolymer coating, PU coating, PU copolymer coating, PEO coating or PEO copolymer coating.

[0018] A battery comprises a shell and an electric core as described above, and the electric core is accommodated in the shell.

[0019] The electric core and the battery have the following beneficial effects:

[0020] The utility model discloses a kind of tabs, which comprises tab body and first adhesive layer, wherein, tab body includes tab main part and tab edge portion, the two sides of the width direction of tab main part are connected with tab edge portion, and first adhesive layer is coated on tab edge portion.The tab provided by the utility model can effectively improve the adhesion between tab edge portion and separator, thereby avoiding the problem of edge warping of electric core, reducing the problem of thickness expansion of battery edge after cycling, and improving the service life and safety of battery.

[0021] The utility model also provides an electric core and a battery, which avoid the problem of edge warping of electric core by applying the above-mentioned tab, reduce the problem of thickness expansion of battery edge after cycling, and improve the service life and safety of battery.BRIEF DESCRIPTION OF DRAWINGS BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic view of a pole piece body provided by an embodiment of the present application;

[0023] Figure 2 is a structural schematic view of a pole piece provided by an embodiment of the present application;

[0024] Figure 3 is a structural sectional view of a pole piece provided by an embodiment of the present application;

[0025] Figure 4 is a partial structural sectional view of an electric core provided by an embodiment of the present application.

[0026] In the drawings:

[0027] 10, positive pole piece; 20, negative pole piece; 30, diaphragm; 301, second adhesive layer;

[0028] 1, pole piece body; 11, pole piece main body part; 12, pole piece edge part;

[0029] 2, first adhesive layer. DETAILED DESCRIPTION

[0030] In order to make the technical problems solved by the present application, the technical solutions adopted and the technical effects reached more clear, the technical solutions of the present application will be further explained below in combination with the drawings and through specific embodiments.

[0031] In the description of the present application, unless explicitly defined and limited otherwise, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] In the present application, unless explicitly defined and limited otherwise, the "upper" or "lower" of the first feature to the second feature can include the direct contact of the first and second features, or it can include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "upper" and "upper" of the first feature to the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0033] In the description of the present embodiment, the terms 'upper', 'lower', 'left', 'right', and the like, orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms 'first' and'second' are only used to distinguish in the description, and have no special meaning.

[0034] In a lithium ion battery, a polymer coating is usually coated on both sides of the thickness direction of the separator, so as to improve the adhesion of the separator to the positive and negative electrode sheets, thereby improving the cycle life of the battery. However, the binding force of the edge of the soft package cell is weaker than the main body part of the cell, and there is more free electrolyte at the top and bottom of the battery cavity, and the edge of the cell is prone to edge warping. With the cycle of the battery, especially at high temperature, the warping of the edge of the cell will be aggravated, so that the battery edge appears swollen and raised, thereby affecting the service life and safety of the battery.

[0035] In order to solve the above problems, as shown in Figures 1-4 The present embodiment provides an electrode sheet, which comprises an electrode sheet body 1 and a first adhesive layer 2, wherein the electrode sheet body 1 comprises an electrode sheet main body part 11 and an electrode sheet edge part 12, the two sides of the width direction (ab direction in the figure) of the electrode sheet main body part 11 are connected with the electrode sheet edge part 12, and the first adhesive layer 2 is coated on the electrode sheet edge part 12. The electrode sheet provided by the present embodiment can effectively improve the adhesion of the electrode sheet edge part 12 to the separator 30 by coating the first adhesive layer 2 on the electrode sheet edge part 12, thereby avoiding the problem of edge warping of the cell, reducing the problem of thickness swelling of the battery edge after cycling, and improving the service life and safety of the battery.

[0036] It should be noted that in the present embodiment, after the rolling of the electrode sheet body 1 is completed, the first adhesive layer 2 can be coated on the electrode sheet edge part 12 by roll coating or spraying.

[0037] In the present embodiment, the first adhesive layer 2 can be a PVDF coating, a PVDF copolymer coating, a PMMA coating, a PMMA copolymer coating, a PMIA coating, a PMIA copolymer coating, a PEI coating, a PEI copolymer coating, a PI coating, a PI copolymer coating, a PAA coating, a PAA copolymer coating, a PU coating, a PU copolymer coating, a PEO coating, or a PEO copolymer coating. The present embodiment does not limit the specific type of the first adhesive layer 2, as long as the first adhesive layer 2 has good adhesion.

[0038] Optionally, in the present embodiment, as shown in Figure 3As shown, the thickness h1 of the first adhesive layer 2 coated on the edge portion 12 of the pole piece is 0.5um-5um. Specifically, in the present embodiment, the thickness h1 of the first adhesive layer 2 coated on the edge portion 12 of the pole piece can be 0.5um, 0.6um, 0.7um, 0.8um, 0.9um, 1um, 1.1um, 1.2um, 1.3um, 1.4um, 1.5um, 1.6um, 1.7um, 1.8um, 1.9um, 2um, 2.1um, 2.2um, 2.3um, 2.4um, 2.5um, 2.6um, 2.7um, 2.8um, 2.9um, 3um, 3.1um, 3.2um, 3.3um, 3.4um, 3.5um, 3.6um, 3.7um, 3.8um, 3.9um, 4um, 4.1um, 4.2um, 4.3um, 4.4um, 4.5um, 4.6um, 4.7um, 4.8um, 4.9um or 5um. The above range of thickness of the first adhesive layer 2 not only ensures the adhesion of the first adhesive layer 2, but also does not affect the performance of the pole piece itself, and can ensure the normal operation of the pole piece. When the thickness of the first adhesive layer 2 is less than the above range, the adhesion of the first adhesive layer 2 cannot be guaranteed, and when the thickness of the first adhesive layer 2 is greater than the above range, the performance of the pole piece itself will be affected, and the flatness of the pole piece and the separator 30 will be reduced.

[0039] Optionally, in the present embodiment, as shown in Figure 3 The ratio of the thickness h1 of the first adhesive layer 2 to the thickness h2 of the pole piece body 1 is 0.3%-5%. Specifically, the ratio of the thickness h1 of the first adhesive layer 2 to the thickness h2 of the pole piece body 1, i.e. h1 / h2 can be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9% or 5%. The above numerical range avoids the thickness of the first adhesive layer 2 being too large to affect the normal performance of the pole piece, and effectively ensures the adhesion effect of the first adhesive layer 2.

[0040] Optionally, in the present embodiment, as shown in Figure 1As shown, the ratio of the width dimension w1 of the tab edge portion 12 to the width dimension w2 of the tab body portion 11 is 4% to 40%. Specifically, in the present embodiment, the ratio of the width dimension w1 of the tab edge portion 12 to the width dimension w2 of the tab body portion 11, i.e., w1 / w2, can be 4%, 6%, 8%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%. The above numerical limitation not only makes the area of the tab body 1 coated with the first adhesive layer 2 relatively small, thereby avoiding affecting the overall performance of the battery, but also effectively avoids the problem of edge warping of the battery cell.

[0041] Optionally, in the present embodiment, the width dimension w1 of the tab edge portion 12 is 0.4mm to 24mm. Specifically, the width dimension w1 of the tab edge portion 12 can be 0.4mm, 0.6mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 10mm, 12mm, 14mm, 16mm, 20mm, 22mm, or 24mm.

[0042] In the present embodiment, as shown, Figure 4 The present embodiment also provides a battery cell, which includes a separator 30 and two above-mentioned tabs, the two tabs being a positive tab 10 and a negative tab 20 respectively, the separator 30 being coated with a second adhesive layer 301 on opposite sides along its thickness direction (the cd direction in the figure), and the positive tab 10 being pasted to one side of the separator 30 along its thickness direction, and the negative tab 20 being pasted to the other side of the separator 30 along its thickness direction. The battery cell provided by the present embodiment, on the basis of ensuring that the separator 30 is coated with the second adhesive layer 301 on opposite sides along its thickness direction, additionally coats the first adhesive layer 2 at the position where the tab edge portion 12 is pasted to the separator 30, which can effectively improve the adhesion between the tab edge portion 12 and the separator 30, thereby avoiding the problem of edge warping of the battery cell, reducing the problem of thickness expansion of the battery edge after cycling, and improving the service life and safety of the battery.

[0043] Optionally, in the present embodiment, the battery cell includes a plurality of positive tabs 10 and a plurality of negative tabs 20, the plurality of positive tabs 10 and the plurality of negative tabs 20 are stacked, and the separator 30 is stacked between adjacent positive tabs 10 and negative tabs 20, thereby forming a stacked battery cell. In other embodiments, the positive tab 10, the negative tab 20, and the separator 30 can also be wound together, thereby forming a wound battery cell.

[0044] It should be noted that, Figure 4The given is only a schematic view, and after the heat-pressing pressure formation of the separator 30, the positive electrode sheet 10, and the negative electrode sheet 20, the two sides of the separator 30 will be tightly attached to the positive electrode sheet 10 and the negative electrode sheet 20, respectively, and the main body part 11 of the electrode sheet and the corresponding second adhesive layer 301 will be tightly attached, without leaving a gap.

[0045] It should be noted that in the present embodiment, the second adhesive layer 301 can be coated on both sides of the separator 30 along the thickness direction thereof by means of roll coating or spraying.

[0046] Optionally, in the embodiment, the thickness h3 of the second adhesive layer 301 coated on the side of the separator 30 opposite in the thickness direction thereof is 0.5 um to 5 um, and specifically, the thickness h3 of the second adhesive layer 301 coated on the side of the separator 30 opposite in the thickness direction thereof can be 0.5 um, 0.6 um, 0.7 um, 0.8 um, 0.9 um, 1 um, 1.1 um, 1.2 um, 1.3 um, 1.4 um, 1.5 um, 1.6 um, 1.7 um, 1.8 um, 1.9 um, 2 um, 2.1 um, 2.2 um, 2.3 um, 2.4 um, 2.5 um, 2.6 um, 2.7 um, 2.8 um, 2.9 um, 3 um, 3.1 um, 3.2 um, 3.3 um, 3.4 um, 3.5 um, 3.6 um, 3.7 um, 3.8 um, 3.9 um, 4 um, 4.1 um, 4.2 um, 4.3 um, 4.4 um, 4.5 um, 4.6 um, 4.7 um, 4.8 um, 4.9 um or 5 um. Optionally, in the embodiment, the thickness h4 of the second adhesive layer 301 coated on the other side of the separator 30 opposite in the thickness direction thereof is 0.5 um to 5 um. Specifically, the thickness h4 of the second adhesive layer 301 coated on the other side of the separator 30 opposite in the thickness direction thereof can be 0.5 um, 0.6 um, 0.7 um, 0.8 um, 0.9 um, 1 um, 1.1 um, 1.2 um, 1.3 um, 1.4 um, 1.5 um, 1.6 um, 1.7 um, 1.8 um, 1.9 um, 2 um, 2.1 um, 2.2 um, 2.3 um, 2.4 um, 2.5 um, 2.6 um, 2.7 um, 2.8 um, 2.9 um, 3 um, 3.1 um, 3.2 um, 3.3 um, 3.4 um, 3.5 um, 3.6 um, 3.7 um, 3.8 um, 3.9 um, 4 um, 4.1 um, 4.2 um, 4.3 um, 4.4 um, 4.5 um, 4.6 um, 4.7 um, 4.8 um, 4.9 um or 5 um. The range of the thickness of the second adhesive layer 301 is set to not only ensure the adhesion of the second adhesive layer 301 but also not affect the performance of the battery cell, so as to ensure the normal operation of the battery cell.

[0047] Optionally, in the embodiment, the second adhesive layer 301 can be a PVDF coating, a PVDF copolymer coating, a PMMA coating, a PMMA copolymer coating, a PMIA coating, a PMIA copolymer coating, a PEI coating, a PEI copolymer coating, a PI coating, a PI copolymer coating, a PAA coating, a PAA copolymer coating, a PU coating, a PU copolymer coating, a PEO coating, or a PEO copolymer coating. The embodiment does not limit the specific type of the second adhesive layer 301, as long as the second adhesive layer 301 has good adhesion.

[0048] The embodiment further provides a battery, which comprises a shell and the above-mentioned battery cell, and the battery cell is accommodated in the shell. It should be noted that the shell is provided with electrolyte, and the battery cell is immersed in the electrolyte. The battery provided by the embodiment reduces the problem of thickness expansion of the battery edge after cycling by applying the above-mentioned battery cell, and improves the service life and safety of the battery.

[0049] Obviously, the above-mentioned embodiments of the utility model are only examples for clearly explaining the utility model, and are not the limitation of the embodiments of the utility model. For ordinary skilled in the art, on the basis of the above-mentioned description, other different forms of changes or changes can be made. Here, it is not necessary and impossible to enumerate all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the utility model should be included in the protection scope of the utility model claim.

Claims

1. A pole piece, characterized in that, The application relates to a polar piece and a battery. The polar piece comprises a polar piece body (1) and a first adhesive layer (2), wherein the polar piece body (1) comprises a polar piece main body part (11) and a polar piece edge part (12), the two sides of the polar piece main body part (11) in the width direction are connected with the polar piece edge part (12), and the first adhesive layer (2) is coated on the polar piece edge part (12). The first adhesive layer (2) is a PVDF coating, a PVDF copolymer coating, a PMMA coating, a PMMA copolymer coating, a PMIA coating, a PMIA copolymer coating, a PEI coating, a PEI copolymer coating, a PI coating, a PI copolymer coating, a PAA coating, a PAA copolymer coating, a PU coating, a PU copolymer coating, a PEO coating or a PEO copolymer coating.

2. The pole piece of claim 1, wherein The thickness h1 of the first adhesive layer (2) coated on the polar piece edge part (12) is 0.5-5 um.

3. The pole piece of claim 1, wherein The ratio of the width dimension w1 of the polar piece edge part (12) to the width dimension w2 of the polar piece main body part (11) is 4%-40%.

4. The pole piece of claim 1, wherein The width dimension w1 of the polar piece edge part (12) is 0.4-24 mm.

5. The pole piece of claim 1, wherein The ratio of the thickness h1 of the first adhesive layer (2) to the thickness h2 of the polar piece body (1) is 0.3%-5%.

6. The pole piece of claim 1, wherein The battery comprises a diaphragm (30) and two polar pieces as claimed in any one of claims 1-6, wherein the two polar pieces are a positive polar piece (10) and a negative polar piece (20), the diaphragm (30) is coated with a second adhesive layer (301) on the two opposite sides in the thickness direction, the positive polar piece (10) is pasted on one side of the diaphragm (30) in the thickness direction, and the negative polar piece (20) is pasted on the other side of the diaphragm (30) in the thickness direction.

7. An electric cell characterized by The thickness h3 of the second adhesive layer (301) coated on one side of the diaphragm (30) in the thickness direction is 0.5-5 um; and / or 8. The electric cell of claim 7, wherein, The thickness h4 of the second adhesive layer (301) coated on the other side of the diaphragm (30) in the thickness direction is 0.5-5 um. The second adhesive layer (301) is a PVDF coating, a PVDF copolymer coating, a PMMA coating, a PMMA copolymer coating, a PMIA coating, a PMIA copolymer coating, a PEI coating, a PEI copolymer coating, a PI coating, a PI copolymer coating, a PAA coating, a PAA copolymer coating, a PU coating, a PU copolymer coating, a PEO coating or a PEO copolymer coating.

9. The electric cell of claim 7, wherein, The battery comprises a casing and an electric core as claimed in any one of claims 7-9, and the electric core is accommodated in the casing.

10. A battery, characterized by ​

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